MyBatis的常用註解以及簡單使用

學習要點

MyBatis的常用註解

MyBatis的常用註解

１.普通對映

@Select("select * from mybatis_Student where id=#{id}")  
public Student getStudent(int id);  
@Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")  
public int insert(Student student);  
@Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")  
public int update(Student student);  
@Delete("delete from mybatis_Student where id=#{id}")  
public int delete(int id);  
 

２.結果集對映

@Select("select * from mybatis_Student")  
@Results({  
    @Result(id=true,property="id",column="id"),  
    @Result(property="name",column="name"),  
    @Result(property="age",column="age")  
})  
public List<Student> getAllStudents();  

３.關係對映

1)一對一

@Select("select * from mybatis_Student")  
@Results({  
    @Result(id=true,property="id",column="id"),  
    @Result(property="name",column="name"),  
    @Result(property="age",column="age"),  
    @Result(property="address",column="address_id",
 
[email protected](select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
})  
public List<Student> getAllStudents();  

2)一對多

package com.skymr.mybatis.mappers;  

import org.apache.ibatis.annotations.Many;  
import org.apache.ibatis.annotations.Result;  
import org.apache.ibatis
 
.annotations.Results;  
import org.apache.ibatis.annotations.Select;  

import com.skymr.mybatis.model.Grade;  

public interface Grade2Mapper {  

    @Select("select * from mybatis_grade where id=#{id}")  
    @Results({  
        @Result(id=true,column="id",property="id"),  
        @Result(column="grade_name",property="gradeName"),  
        @Result(property="students",column="id",[email protected](select="com.skymr.mybatis.mappers.Student2Mapper.getStudentsByGradeId"))  
    })  
    public Grade getGrade(int id);  
}  

package com.skymr.mybatis.mappers;  

import java.util.List;  

import org.apache.ibatis.annotations.Delete;  
import org.apache.ibatis.annotations.Insert;  
import org.apache.ibatis.annotations.One;  
import org.apache.ibatis.annotations.Result;  
import org.apache.ibatis.annotations.Results;  
import org.apache.ibatis.annotations.Select;  
import org.apache.ibatis.annotations.Update;  

import com.skymr.mybatis.model.Student;  

public interface Student2Mapper {  

    @Select("select * from mybatis_Student where id=#{id}")  
    public Student getStudent(int id);  
    @Insert("insert into mybatis_Student (name, age, remark, pic,grade_id,address_id) values (#{name},#{age},#{remark}, #{pic},#{grade.id},#{address.id})")  
    public int insert(Student student);  
    @Update("update mybatis_Student set name=#{name},age=#{age} where id=#{id}")  
    public int update(Student student);  
    @Delete("delete from mybatis_Student where id=#{id}")  
    public int delete(int id);  

    @Select("select * from mybatis_Student")  
    @Results({  
        @Result(id=true,property="id",column="id"),  
        @Result(property="name",column="name"),  
        @Result(property="age",column="age"),  
        @Result(property="address",column="address_id",[email protected](select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
    })  
    public List<Student> getAllStudents();  
    @Select("select * from mybatis_Student where grade_id=#{gradeId}")  
        @Results({  
        @Result(id=true,property="id",column="id"),  
        @Result(property="name",column="name"),  
        @Result(property="age",column="age"),  
        @Result(property="address",column="address_id",[email protected](select="com.skymr.mybatis.mappers.AddressMapper.getAddress"))  
    })  
    public List<Student> getStudentsByGradeId(int gradeId);  
}  

４.動態sql註解對映

provider類

package com.skymr.mybatis.mappers.provider;  

import java.util.Map;  

import org.apache.ibatis.jdbc.SQL;  

import com.skymr.mybatis.model.Student;  

public class StudentDynaSqlProvider {  

    public String insertStudent(final Student student){  
        return new SQL(){  
            {  
                INSERT_INTO("mybatis_Student");  
                if(student.getName() != null){  
                    VALUES("name","#{name}");  
                }  
                if(student.getAge() > 0){  
                    VALUES("age","#{age}");  
                }  
            }  
        }.toString();  
    }  

    public String updateStudent(final Student student){  
        return new SQL(){  
            {  
                UPDATE("mybatis_Student");  
                if(student.getName() != null){  
                    SET("name=#{name}");  
                }  
                if(student.getAge() > 0){  
                    SET("age=#{age}");  
                }  
                WHERE("id=#{id}");  
            }  
        }.toString();  
    }  

    public String getStudent(final Map<String,Object> map){  
        return new SQL(){  
            {  
                SELECT("*");  
                FROM("mybatis_Student");  
                if(map.containsKey("name")){  
                    WHERE("name like #{name}");  
                }  
                if(map.containsKey("age")){  
                    WHERE("age=#{age}");  
                }  
            }  
        }.toString();  
    }  

    public String deleteStudent(){  
        return new SQL(){  
            {  
                DELETE_FROM("mybatis_Student");  
                WHERE("id=#{id}");  
            }  
        }.toString();  
    }  
}  

Mapper介面

@SelectProvider(type=StudentDynaSqlProvider.class,method="getStudent")  
public List<Student> getStudents(Map<String,Object> map);